In this paper, a novel single-stage modular multilevel converter (MMC) is proposed for single-phase AC–DC applications. Although connected directly to the AC port, the MMC requires only half-bridge submodules. This is enabled by the use of bidirectional switches and by imposing a reduced-magnitude fraction of the AC port voltage onto the individual submodule capacitors. To the author’s knowledge, this is the first known work that proposes using a half-bridge string of ac sources. The converter is operated such that the inherent twice-line-frequency power pulsation is shifted to the DC port, resulting in submodule capacitor requirements that are based on the switching frequency currents. Moreover, similar to a flying-capacitor converter, it is possible to switch only a subset of the half-bridges in an operating cycle, enabling a switching frequency multiplicative effect.
